Production of white lead



Jul 9, 1929. F. T. BAlLEY ET AL 1,720,196

PRODUCTION OF WHITE LEAD Filed Jan. 28, 1925 Q INVENTORJ v/M Arrolzws.

0 conditions.

Patented 'July 9, 19 29.

UNITED STATES PATENT OFFICE.-

rrmnx 'r. BAIILEY AND WILSON AUSTIN, on NEW YORK, n. Y.

PRODUCTION OF WHITE LEAD.

Application filed January 28 1926. Serial No. 84,277.

This invention relates to the production of white lead and has for an object a method of producing white lead in a highly expeditious and more economical manner. together with an apparatus for performing the method.

- According to this invention, lead oxides, hydrated lead oxide, or, if desired, a mixture or combination'of these with lead dust, water, and asuitable activating agent or carrier are placed within a closed rotatable drum provided with rotatable heaters by means of which the charge in the drum is Whipped in a more or less continually changing atmosphere of proper gases, the supply, proportion and temperature of which are subject to control. The main body of the liquid in the drum is preferably below the path of the rotating heaters and is repeatedly raised by the rotating drum and spilled over the heaters. In this manner the falling charge is struck violent glancing blows which break it up into very fine particles and impart heat to the charge by impact and frictional attrition of the particles against each other as Well as against the heaters, thereby bringing the entire charge repeatedly into intimate contact .with the proper gases and at a proper temperature with the result that the chemical re actions take place imder the most favorable Furthermore, as white lead is formed on the surface of these minute particles it is ground off by attrition thus exposing the underlying and uncorroded portions of the particles continually to the action of the corroding agents. This expedites the formation of white lead and increases the degreeoi' corrosion or the percentage of white lead produced from a given charge thus effecting a considerable economy of operation.

By passing a carefully regulated mixture of. gases more or less continually through the drum and by reason of the closed drum and the regulating valves the proper atmosphere and temperature can always be maintained and the gases at the outlet end maybe regained and passed along to other corroding units thereby effecting an unusual economy not at present obtainable.

By adjustment of the flow, proportions, temperature and amount of the gases, and the control of the speed of rotation of the drum and the heaters, proper accommodation can be made for. widely varying degrees of oxidation in the initial charge of oxidized lead particles or varying mixtures of such oxides and lead dust. so that commercially practical corrosions can he obtained in an unusually short time. By a careful regulation of these factors a. 100% corrosion of the charge introduced into the drum may be obtained. The

resultant product is of an exceptionally high A manhole closed by the manhead 4 is .pro- 1 vided for introducing or removing a charge from the drum. The heads 2 and 3 carry spiders 5 and 6 respectively in which are journaled the ends of a shaft 7 theshaft passing through suitably packed apertures in the heads 2 and 3. Removable end pieces on packings 24 may be provided at each end so that, as the packing is worn by the friction of the revolving shaft, other fittings may be substituted. The shaft 7 carries a plurality of heaters 8, preferably of a triangular cross section. Diamond shaped heaters or other forms calculated to strike glancing blows may likewise be used with equal effect. The shaft 7 with the heaters is driven through the medi um of a pullev 9. On the interior of the drum are provided ribs 10 for raising the charge from the bottom of the drum and dropping it on the heaters. The drum is supported on rollers 11 mounted on a shaft 12 which is driven in any suitable manner and which 'is provided with a pinion 13 meshing with a. gear 14 on thedrum by means-of which the latter may be driven. Shields 19 and 20 re, tain the charge in the main body of the drum and prevent clogging of the inlet and outlet. Near the end of the drum opposite to that at which the mixture of gas is admitted, the

shaft? is providedwith suitable holes 17 may be used again or be used in connection with the source of supply for other drums repeating the same operation as described.

In the operation of this machine and process white lead is produced by the combined 'action'of an, water and an activating agent or carrier, more or less completely 'OX1d1ZO(l lead particles, hydrated lead oxidcs, or a mixture or combination of same with lead 'dust, to form basic lead compounds, whlch in turn react with the carbonating agent employed to form basic carbonate of lead, or White lead, the activating agent or product being released to again attack the uncorroded particles of the initial charge. For example, when acct ic acid is used as the activating agent the basic lead compound formed is the basic acetate or a mixture of the acetate and hydroxide and when this reacts with a carbonatin g agent, such as carbon dioxide, white. lead is formed and acetate of lead is released to again attack the more or less completely oxidized lead particles, hydrated lead oxides, or mixture of same with finely comminuted lead dust. The use ofour method and apparatus for conducting and also accelerating I these last mentioned chemical reactions may be described as follows, although we do not restrict ourselves to the use of any particular activating and carbonating agents.

There is introduced into the drum 1-. a charge consisting of water, an activating agent and granulated or comminuted' lead particles more or less completely oxidized, although a mixture of such oxides and lead dust may also be used. The drum is rotated at a speed of approximately twenty revolutions perminute and the beaters 8 are revolved preferably in a. similar peripheral direction at a speed between two hundred and four hundred revolutions per minute for the ordinary sizemachine. The speed of the heaters should be varied in-accordance witlrth'e size of the machine, as the attritional effect is relative.

to the peripheral speed of the beaters rather than their angular speed. The amount of the charge admitted into the drum preferably is such that the beaters in their rotation do not strike the main body of liquid in the bottom of the drum. The charge is repeatedly lifted by the ribs 10 as the drumrotates and is showered down-on'the beaters. However,

the same result may be obtained without such ribs by the mere rotation of the drum and the action regulated by the adjustment of the speed of the drum.

Either a mixture of carbon dioxide with air, or, first air followed by carbon dioxide and air, such asmay be obtained practically by a direct connection with a furnace, or from the outlet end of another drum in conjunction with a furnace connection, is admitted to the drum through the inlet tube 16.

This tube is provided witha valve 15 for regulating the quantity of'gas admitted to the chamber. Preferably also there is provided in the tube adjustable means for admittinga definite amount of additional air to the mixture so that the proper ratio of carbon dioxide and air may bemaintained. This proper ratio varies under different conditions and with different character-pf charges,

vbut anexample' would be approximately seven parts of air to one of carbon dioxide. Such adjustment may be secured by providing suitable air holes 20 in the tube 16 and by providing for their adjustment by a slide collar 21.

The rotating beaters strike the falling particles as the charge is repeatedly spilled from the ribs 10 by the rotation of the drum 1 while they aresuspended in the atmosphere impact of the particles against the beaters and other particles and raises their temperature momentarily to a high degree and at the same time brings them into intimate contact with the atmosphere in the drum which is maintained at the proper proportions of air and carbon dioxide with the result that the chemical reactions take place under the most favorable conditions and are therefore completed with great rapidity. The attrition also serves-to grind off the white lead as formed on the surface of the particles, thereby exposing the underlying and-uncor'roded portions of the particles directly to the action of the corroding agents. This makesthe corrosion of white lead almost entirely a sur-v face action which facilitates and therefore accelerates the process and gives a highv degree or percentage of corrosion. When the charge has reached the degree of corrosion desired it-' may then be removed from the able manner. 1

As the endsofthe drum are closed and theopenings through which the shaft 7 drum and the white leadtreated in any suitpasses'are packed, there is no way for air or carbon dioxideto'be brought into contact with the charge except through the valve 15. The amount of air and carbondioxide suppliedcan therefore be regulated very exactly. When the carbon dioxide 1s secured direct from a furnace, the valve 15 may also be used as a means of preventing the overheating of the contents of the chamber by the hot gas from the furnace. In general,

a certain amount of heat in the gas and the ing through the chamber. In the manner described, the proper atmosphere may be provided to cause, in conjunction with the violent attrition of the lead oxide particles in the presence of the activating'agent, the production of white lead in the most efiicient manner. It has been found, however, that it is necessary or desirable to maintain a circulation of the gases through the drum in order to insure the maintenance of a. proper strength of the gases and this is accomplished by means of a continuous stream of 'properly regulated gas passing through. the drum, or an intermittent flow of the her and suitable means provided individually for re lating the rate at which each is introduce It is also possible to introduce the carbon dioxide and air into the chamber alternately with the proper control so as to provide the proper resulting atmosphere within the drum.

It is, of course, understood that various modifications may be made in the structure of the above-described apparatus for producing white lead without in any way departing from the spirit of the invention as set forth in the appended claims. The apparatus is likewise capable of many other uses than as above specified, being suitable for securing an intimate union or mixture ofliquids and gases and it is to be understood that its application is to not be limited to the production of white lead.

What we claim as new and desire to secure by Letters Patent of the United States is;

1. The process of making corroded white lead which comprises introducing a water mixture of lead oxide and acetic acid into a closed container, whipping said mixture in atmospheric suspension while revolving said container, admitting air to said container and discharging 1t therefrom, and circulatlng-carbon dioxide through said chamber at a definite rate.

2. The process of making corroded white lead which comprises whip ing atmospherically suspended particles of a water mixture of lead oxide and lead, adding acetic acid, circulating air through said mixture, and directmixture. 3. The process of making corroded white ing a stream of carbon dioxide through saidlead which comprises whipping particles of lead in atmospheric suspension in any stage of'oxidation in the presence of water and acetic acid, and circulating a regulated atmosphere of air and carbon dioxide into contact with said particles.

4. The lead whic comprises repeatedly whipping particles in atmospheric suspension of any of the lead oxides in the presence of water and acetic acid and in a regulated circulating atmosphere of air and carbon dioxide.

5. The process of making corroded white lead which comprises repeatedly whipping particles of lead oxide suspended in a circulating atmosphere of air and carbon dioxide in the presence of water and an activating agent, and regulating the circulation and composition of said atmosphere.

6. The process of making corroded white lead which comprises repeatedly whipping particles of lead oxide suspended in a circulating atmosphere of air and carbon dioxide in the presence of water and an activating agent, and. regulating the circulation composition and temperature of said atmosphere.

7 .'The process of'making corroded white lead which comprises repeatedly whipping a mixture of lead oxide, water and acetic acid suspended in a regulated circulating mixture of air and carbon dioxide and controlling the temperature of the mixture.

8. The process of making corroded white lead which comprises whipping particlesof lead oxide suspended in a regulated circulating oxidizing and carbonating atmosphere in the presence of Waterand an activating agent.

In testimony whereof, we have signed our names to this specification.

rocess of making corroded White 

